This Resource is concerned with conceiving, designing, developing, and understanding the principles, limitations, and applications of silicon biomedical transducers. Such transducers are made using advanced integrated-circuit technology, and are intended for in-vivo and noninvasive measurements. Transducers for measuring force, absolute pressure, acceleration, temperature distribution and pressure distribution have been made using IC batch fabrication processes for uniformity and eventual low cost. New transducers for specific applications are being developed in close contact with selected biomedical collaborators who have an identified need and use for them; in many cases transducers can be supplied by the Resource to other collaborators or users as interest, need and availability permit. Together with help from its collaborators, the Resource can provide information and assistance to new investigators who wish to use the transducers. In order to improve the stability and the in-vivo durability of the transducers, research attention is now being focussed on improved lead-attachment techniques and on incorporating signal conditioning circuitry right on the transducer. Individual sensors can be very small and light in weight. The absolute pressure transducer is only 1 x 1.2 x 0.4 mm. The accelerometer weighs less than 0.02 gm, thus introducing negligible measurement artifact. Sensitivity to measurement of mechanical quantities is large, because silicon has a very high strain-gauge factor. Biocompatibility is achieved using inert materials (silicon, pyrex glass) and with coatings of inert polymers.